Antimicrobial liquid cleansing products such as antibacterial soaps and hand sanitizers have risen in popularity over the past decade and are now a billion-dollar industry. Such antibacterial cleansers were once largely confined to medical settings. Virulent outbreaks of bacterial infections including Escherichia coli and Listeria monocytogenes among the general population in recent years, however, have fueled consumer demand for personal care products that eliminate skin microorganisms. Such consumer demands are reflected in the market place. For example, a recent survey of soap products currently on the market determined that about 75% of liquid soaps contain antibacterial agents.
The antibacterial compound most frequently found in consumer products is 5-chloro-2-(2,4-dichlorophenoxy)phenol, more commonly known as triclosan. Triclosan has been in use for decades and is present in almost half of the liquid soaps currently on the market. Triclosan can also be found in hundreds of other product categories, including toothpaste, clothing, and toys. Triclosan has proven broad-spectrum efficacy against most Gram-positive and Gram-negative bacteria. The compound exerts bactericidal activity through multiple mechanisms, including the inhibition of fatty acid synthesis in bacterial cells. In personal care products, triclosan is generally used in an amount of about 0.1 weight percent (wt %) to about 0.5 wt %, based on the total weight of the composition, in order to provide sufficient antimicrobial activity. For example, a commercially available antibacterial cleansing composition containing 0.5 wt % triclosan and 5.4 wt % lactic acid/lactate in a liquid soap base comprising water, about 4 wt % sodium laureth sulfate, 4 wt % sodium cumenesulfonate, 10 wt % propylene glycol, and 1 wt % cocamidopropyl betaine and having a pH of about 4.5 is known in the art. Other antibacterial cleansing compositions known in the art having pH values between about 4.2 and 4.5 comprise about 0.3 wt % triclosan and 10 wt % lactic acid/lactate as active antimicrobial agents in a similar liquid soap base further including about 4.5 wt % ethyl alcohol.
The safety of triclosan is controversial, however. Some scientists have warned that overuse of the compound could cause resistant strains of bacteria to develop. There is also concern over the effects of triclosan on humans. The chemical has been found to accumulate within the body, and recent studies have linked triclosan to the development of allergies and disruption of hormone regulation. Because of the potential safety issues associated with triclosan, some consumer groups have called for a ban on its use. Indeed, the hazards of triclosan are reflected in its registration as a pesticide with the Environmental Protection Agency. In view of the aforementioned health concerns, both the Food and Drug Administration and Environmental Protection Agency are currently re-evaluating the safety of triclosan in consumer products. However, despite concerns over triclosan's safety, its use remains widespread due to the compound's superior antibacterial properties. With the safety of triclosan in question and an unwaning threat of harmful bacteria, however, there exists a need for antibacterial consumer products that are triclosan-free, but still effective at killing microorganisms, particularly in areas or situations where infection is medically indicated, such as in hospitals, in community medical facilities, in dental institutions, in clinics of schools and of nursing homes, in the workplace, and in the home.